1. Field of the Invention
This invention relates to a rail joint, more particularly to a rail joint which is used for interconnecting two successive rail bars of a railroad track so as to reduce vibration and noise generated by a train when the train passes over the rail joint of the railroad track.
2. Description of the Related Art
The improvement of this invention is directed to a conventional rail joint which is used for interconnecting two successive rail bars of a railroad track.
Referring to FIG. 1, a railroad track 10 includes two rows of successive rail bars 11 which are fixed on several transverse sleepers 12 in a known manner and which support wheels 20 (only one is shown) of a train thereon. Any successive two of the rail bars 11 form an expansible space 13 between their adjacent end portions so as to permit thermal expansion of the rail bars 11. The successive rail bars 11 are then connected to each other by means of a conventional rail joint to ensure alignment of the successive rail bars 11 in order to avoid violent vibration of the successive rail bars 11 when the wheels 20 of the train pass over the expansible space 13, thereby minimizing unsteady movement of the train. The conventional rail joint usually includes a pair of fishplates 14 (only one is shown) which are mounted securely to two opposite side walls of the successive rail bars 11 by means of bolts 15. However, owing to the frequent thermal expansion and contraction of the successive rail bars 11, the bolts 15 are easily loosened from the successive rail bars 11 to result in untimely removal of the fishplates 14 from the successive rail bars 11. Thus, the expansible spaces 13 in any two adjacent end portions of the rail bars 11 cannot be maintained at equal distances. This results in violent vibration of the train when the wheels of the train pass over the unequal expansible spaces 13. Accordingly, it is necessary to inspect frequently the combination of the bolts 15 and the successive rail bars 11 to ensure that the fishplates 14 remain mounted securely to the successive rail bars 11.
In addition, the adjacent end portions of the successive rail bars 11 are respectively provided with vertical and flat end surfaces. As the train moves along the railroad track 10, each wheel 20 of the train is transferred from the adjacent end portion of one of the rail bars 11 onto the adjacent end portion of the other one of the rail bars 11 within a very short time such that the adjacent end portion of the other one of the rail bars 11 has to burden instantaneously the weight carried by the wheel 20. As a result, the impact of the wheel 20 with the other one of the rail bars 11 during the transfer process may result in violent vibration of the train and in a very loud noise.
In order to overcome the above described drawback, an improved railroad track has been disclosed in U.S. Pat. No. 207,792. As disclosed, each of opposed end portions of each of aligned rail bars of the railroad track has an inclined end face that is parallel to an inclined end face of an adjacent one of the rail bars. The inclined end faces are oriented at a predetermined angle relative to the longitudinal axes of the rail bars. Accordingly, when a train moves along the railroad track, one wheel of the train is transferred gradually from a previous rail bar to a succeeding adjacent rail bar so as to reduce the impact of the wheel with the end portion of the adjacent rail bar, thereby consequently generating less noise and vibration.
However, the impact of the wheel with the end portion of the adjacent rail bar easily causes damage to a pointed end of the inclined end surface of the end portion of the adjacent rail bar. Thus, the rail bars of the railroad track have to be replaced frequently.